Abstract: My invention relates to heat engines. It has the following objectives: 1) Efficient conversion of any source of heat into useful mechanical power. 2) A novel proportional control valve system based on rotary refrigerant valves controlled by a programmable logic controller (PLC). This proportional valve system allows rapid response to any output power requirement. The PLC adjusts between energy supply and load requirements almost instantly. This also permits a servo mode implementation. 3) Uncontrolled runaway operation is impossible. Under adverse conditions, the system automatically de-powers. System integrity shall be maintained under all fault conditions unless an external force destroys the invention. 4) Internal heat storage inside the invention permits a slow rate of change for energy input. 5) The implementation of this invention provides for ease of construction from prototype to production of any size or scale.